In light of Pierce Brosnan's brave, warbling turn in Mamma Mia—as well as recent news that Kate Hudson would veer off the Bongo Romcom highway to explore the musical theater side roads in Rob Marshall's Nine—Defamer videologist Molly McAleer has compiled a countdown of 10 Classic Musical Crossover Performances. We've ordered these from least to most successful; some of these actors-who-sing are arguably better singers than they are actors, and have gone on to cut their own records. Some are clearly better actors than singers. And some should probably just give up both and become something sensible like a dental hygienist or insurance broker. We have no doubt you have your own strong opinions on notable omissions; feel free to post video in the comments.

10. Tom Cruise, Top Gun

9. Renee Zellwegger, Chicago

8. Keira Knightley, Edge Of Love

7. Nicole Kidman, Moulin Rouge

6. Rupert Everett, My Best Friend's Wedding

5. Diane Keaton, Radio Days

4. Scarlett Johansson, Lost In Translation

3. Gwyneth Paltrow, Infamous

2. Zooey Deschanel, Elf

1. Heath Ledger, 10 Things I Hate About You